Among the bigger news items to come out of Mobile World Congress this year was the real-life launch of Mozilla’s Firefox OS, a challenger to the ecosystem ruled by Google and Apple. In our interview with Johnathan Nightingale, Mozilla’s VP of Firefox engineering, he discusses the company’s play for a piece of the ever-increasing mobile web marketplace.

JOHNATHAN NIGHTINGALE: Last year our announcement was “Hey, we’re gonna get into the smartphone OS trade” but mostly we were talking about vision. This year we get to prove it and come back with devices. We have 18 operators and real manufacturers now. This year we got a much bigger booth, and it was packed to the gills.

QUALCOMM SPARK: Why do we need a new mobile OS?

JOHNATHAN NIGHTINGALE: Well, can we tolerate more competition than the duopoly we’ve got? I think we can. It’s not our goal to get to 100% market share. If we get to 10%, 20%, 50%, we’ll have big parties, I promise.

QUALCOMM SPARK: Is this optimism driven by a booming mobile market, especially in developing nations?

JOHNATHAN NIGHTINGALE: Our CEO talks about how we’re going to have 2 billion people joining the web for the first time and we’ve got about 2 billion on the web now, so the next 2 billion is going to look very different. A lot of people are asking whether Firefox OS is designed for the emerging market. Certainly, seeing as that’s an important place for us to be, being a non-profit organization.

JOHNATHAN NIGHTINGALE: We’re really proud of the performance enhancements we’ve made to allow it to run on that class of hardware. Five years ago, you saw the birth of iOS and Android but the web couldn’t do it, and Google is still saying you need native applications to have rich capability. Five years ago that was true, but now that feels really outdated.

QUALCOMM SPARK: Do you think they’ll be more OS competitors in this space, such as Facebook?

JOHNATHAN NIGHTINGALE: I hope so. But a lot [of players] are hamstrung into trying to run the same playbook that worked for Apple and Google. I don’t think you can do that in 2013. However, someone saying we need a third or fourth platform is a really hard sell. And it ignores a key reality: There are 200,000 iOS developers, 600,000 Android developers and 8 million web developers. If you’re not betting on HTML 5, you’re making a mistake.